X+Y=180 1/4X+2/5Y=60
来源:学生作业帮助网 编辑:六六作业网 时间:2024/12/23 11:59:31
X+Y=1801/4X+2/5Y=60X+Y=1801/4X+2/5Y=60X+Y=1801/4X+2/5Y=60x+y=1801/4x+2/5y=60y=180-x1/4x+2/5*(180-x)=
X+Y=180 1/4X+2/5Y=60
X+Y=180 1/4X+2/5Y=60
X+Y=180 1/4X+2/5Y=60
x+y=180
1/4x+2/5y=60
y=180-x
1/4x+2/5*(180-x)=60
解得x=80
y=180-80
=100
x=180-y
再代入
x=80
y=100
最简单的办法是代入法,可以将第一个式子变为含一个变量的式子再代入第二个式子,这时的式子就只有一个未知数了,解出来再代入第一个式子,就可以得出另一个未知数了,如楼上所说~~
天,这么简单的问题你都不会啊?两个方程联立消去X或者Y,不就解出来了吗?
例X=1 y=21.X+Y=5 X-Y=15 2.2X+3Y=4 5X+6Y=7 3.X+3Y=5 3X+Y=-1 4.2X+Y=3 3X+5Y=11 5.4X+3Y=6 2X+Y=4 6.X+Y=180 X=3Y-10 7.3X-2Y=3 2X-Y=7 8.5X+3Y=7Y X+Y=45 9.3X+4Y=126X+8Y=24 X:6Y=1:4 10.X+Y=138 X-45=Y+53 11.X+Y=60 14Y=20X 12.2X+3Y=15.5 5X+6Y=35 13.X+Y=170 3
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
x*x+2x+y*y-4y+5=0 x= y=
3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2
{3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1
4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11
3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27
{6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1
(x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5)
{x+y=1 ,xy=-6{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0
x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2
先化简再求值(x-y)(x-2y)+(x-2y)(x-3y)-2(x-3y)(x-4y) x=4 y=5
若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值
3x-2y=1 4x-5y
(x-y)/4+(x+y)/5=1/4 (x+y)/9-(x-y)/3=//2(x-y)/4+(x+y)/5=1/4(x+y)/9-(x-y)/3=//2
{(x+y)/2+(x-y)/3=1,(x+y)-5(x-y)=2.求x=?,y=?
x+y+2(-x-y+1)=3(1-y-x)-4-(y+x-1),x+y=?
已知x*x+4x+y*y-2y+5=0,则x*x+y*y=?